Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

PURPOSE: The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. METHODS: We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. RESULTS: Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. CONCLUSIONS: The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

Analysis of Refractive Error and Corneal Asphericity in Elementary School Students in Ilsan City

PURPOSE: To determine the relationships among refractive error, corneal asphericity, and axial length in elementary school students. METHODS: One hundred eleven eyes from 56 subjects were included in this study. All subjects underwent cycloplegic refraction corrected to the spherical equivalent. Axial length was measured, and corneal topography was performed. Corneal asphericity was assessed using eccentricity (e) calculated according to the formula Q=-e2. The relationship among spherical equivalent, asphericity, and axial length was determined using a linear regression model. RESULTS: Subjects were between 8 and 12 years of age (mean, 9.99+/-1.33). The average spherical equivalent was -1.38+/-2.08D (-7.13~2.63D), the average axial length was 23.84+/-1.17 mm (20.10~26.37 mm), and the average corneal asphericity was -0.29+/-0.10 (-0.55~-0.07). An increase in myopia was positively correlated with an increase in axial length (p<0.0001). The degree of myopia was negatively associated with corneal asphericity (p=0.019). An increase in axial length was related to an increase of negativity in asphericity (p=0.012). CONCLUSIONS: An increase in myopia was correlated with an increase in axial length. As the degree of myopia and axial length increased, corneal asphericity became more prolate. A longitudinal study with more subjects is required to validate these results.

Comparison of Prostate Volume Measured by Transrectal Ultrasonography and MRI with the Real Prostate Volume Measured after Radical Prostatectomy / 대한비뇨기과학회지

PURPOSE: The aim of this study was to compare the prostate volume, as measured by transrectal ultrasonography (TRUS) and by MRI, with that of the real prostate volume measured after a radical prostatectomy (RRP). MATERIALS AND METHODS: This prospective study included 21 clinically localized prostate cancer patients that had undergone a RRP. TRUS prostate volumes were calculated using the prolate ellipsoid volume formula, with the anteroposterior diameter measured from the axial (TRUS_V1) and midsagittal images (TRUS_V2). Two prolate ellipsoid volumes (MRI_EV1 and MRI_EV2) were calculated from the MRI using the same method, and planimetric volume (MRI_PV) with 3D image software. The real prostate volume (Real_V) was measured in a measuring jug within 1 hour after RRP. RESULTS: The average age and preoperative serum prostate-specific antigen (PSA) were 65.5 years (54-70) and 6.8ng/ml (2.5-17.0), respectively. Mean of Real_V, TRUS_V1 and TRUS_V2 were 40.3ml (21.0-82.0), 42.4ml (23.8-82.2) and 51.4ml (29.1- 87.3), respectively. The mean of MRI_EV1, MRI_EV2 and MRI_PV were 44.2ml (17.9-85.2), 41.0ml (15.7-93.9) and 40.9ml (19.4-83.8), respectively. In a paired sample test, the correlation coefficients (R) for all methods used were over 0.8. In a Student's t-test (paired), the MRI_PV (p=0.620), MRI_ EV2 (p=0.703) and TRUS_V1 (p= 0.099) showed no significant differences compared to the Real_V. The linear regression models of this three methods were y=1.025x 0.268, y=0.946x 2.979 and y=1.046x 0.381, respectively. CONCLUSIONS: Between the TRUS prolate ellipsoid volumes, the TRUS_V1 was shown to be superior to the TRUS_V2. In the MRI, the MRI_EV2 was more accurate than the MRI_EV1. However the MRI_PV was the most accurate method. The TRUS_V1, MRI_EV2 could be used instead of the MRI_PV in general clinical settings.

Estimating the Volume of Pericardial Effusion by M-Mode and 2-D Echocardiographic Method

BACKGROUND: This study was undertaken to test the validity of M-mode and a new cross sectional cehocardiographic quantification of pericardial effusion. METHODS: This study was performed in 12 patients with large pericardial effusion of whom hed M-mode and 2-D echocardiography just before therpeutic drainage of the effusion. The volume of Pericardial fluid removed by pericardiocentesis was compared with te echo-free space estimated by M-mode echocardiography and the volume estimated by new 2-D echocardiographic method. The pericardial sac volume and the cardiac volume were calculated by applying the formula for the volume of a prolate ellipse. RESULTS: 1) There was a good correlation between 2-D echocardiographic estimate and the actual volume removed by pericardiocentesis(r=0.72, p<0.05). 2) The correlation between the echo-free space estimated by M-mode echocardiography at the level of mitral valve and the actual volume was also good(r=0.81,p<0.001). CONCLUSION: The M-mode and 2-D echocardiographic method is successful in helping to estimate large pericardial effusion.

Correlation between Age, Prostatic Volume and Voiding Symptoms in Randomly Selected Korean over Age 60 / 대한비뇨기과학회지

Until now, we do not have specific Korean data on the age related prostatic volume and voiding symptoms associated with prostatic volume among randomized aged population. Due to this problem, we studied the correlations on the age, prostatic volume and voiding symptom among random sampled 255 people over the age 60 from the 11 Myun in Chinyang Gun, Kyungsangnam-do from the July 12th to July 26th, 1993. The mean age of the examined people was 71.5 years. 244 people answered on questionaire for voiding symptom scoring and 224 people agreed on the transrectal ultrasonic measurement of the prostatic volume. The prolate spheroid method and elliptical method were used for the measurement of the prostatic volume with the major transverse diameter, major anteroposterior diameter and cephalocaudal diameter of each prostates as Terris. The volume of the prostate ranged from 6.2cc to 54.5cc ( Prolate spheroid method ) and 4.7cc to 44.1cc(Elliptical method ). The prostate volumes measured by the elliptical method were smaller than that measured by prolate spheroid method in each age group. The average prostatic volume measured by the elliptical volume and prolate spheroid method were 17.7/22.5cc(E/P) in age 61 to 65 group(n=17), 19.9/22.8cc in age 66 to 70 group(n= 88), 21.6/ 26.0cc in age 71 to 75 group(n=71), 24.4/27.7cc in age 76 to 80 group(n=34) and 18.1/23.7cc in age over 80 group(n =14) and the pattern of the changes in the prostatic volume related with aging was significant(p 0.05).

The relationship among PSA levels, prostatic volume and resected prostate weight / 대한비뇨기과학회지

The prostate-specific antigen is a serine protease which is found only in epithelial cells of prostatic origin. Benign and malignant primary, as well as metastatic prostate cells, elaborate this protein. Benign prostatic hyperplasia can be associated with elevated levels of PSA as determined by a monoclonal assay, and prostatic weight is the most important non-cancer factor variable of PSA elevation. We estimated the in vivo prostate gland volume and resected weight of prostate in 75 men using prolate ellipse formula ultrasound analysis from Jan. 1991 to June 1992. OF the men 43 (58 %) had a PSA value of 4ng/ml or less. The PSA value was greater than 4 but less than or equal to 10 in 19 men (25 %) and greater than 10 in 13 men (17 %). A total of 24 men (35 %) had a eland volume less then 25 cm3, 16% of whom had a PSA value greater than 4. Further analysis revealed that the incidence of a PSA value greater than 4 increased as the prostate volume increased (51 % for greater than or equal to 25 but less than or equal to 50 and 62.5 % for greater than 50). The incidence of a PSA Value greater than 10 increased as resected weight of prostate increased (25 % for greater than or equal to 21 but less than or equal to 30 and 75 % for greater than 30). We found a statistically significant association between prostate gland volume and resected specimen weight to the serum PSA concentration. The prostate gland volume can be a helpful adjunct in determining the significance of PSA value clinically.